We are attempting to ascertain the chemical difference between RNA sequences whose processing and/or translation is prohibited by the plant growth regulator abscisic acid (ABA) during the embryogenesis and germination of cotton seeds. Proteins whose synthesis is allowed by ABA are being identified as well as those whose synthesis is proscribed. mRNAs for certain of these proteins are to be isolated and used for the synthesis of cDNA. This DNA, in turn, will be used to quantitatively probe for the cellular location and chemical form of the RNA sequences complementary to it. It is hoped that the mechanism of the ABA inhibition of the synthesis of specific proteins can be identified in this fashion. Furthermore, chemical differences between the two RNA subsets will be looked for.